Remington Arms Co. introduced their 12-gauge, five-shot, John M. Browning designed, "Remington Autoloading Gun" in 1905. From the 1906 Remington Arms Co. catalogue.
Remington was on a roll in 1906 and 07. Their professional shooter William Heer carried the high average for 1906, shooting a pair of their hammerless doubles.
Then J.J. Blanks won the 1907 Grand American Handicap with the Remington Autoloading Gun.
The company name was changed to Remington Arms - Union Metallic Cartridge Co. in 1911. Shortly after that Rem-UMC began calling that gun the Model No. 11. It was during the Rem-UMC years that the buffer begins appearing in the parts lists. In 1920 the company name changed again to Remington Arms Co., Inc. Circa 1927/8 they changed the safety from the lever inside the trigger guard to a crossbolt behind the trigger. In 1930, they introduced the 20-gauge Model 11. Model 11 20-gauge serial numbers began at 1,000,000. In 1931, they added the 16-gauge to the line with 16-gauge serial numbers starting at 1,500,000. In 1930, they also introduced a three-shot version in 20-gauge called "The Sportsman." The 20-gauge “The Sportsman” had serial numbers beginning low 1? Maybe 1000? They added 12- and 16-gauge "The Sportsman" in 1931, with 12-gauge "The Sportsman" having serial numbers starting at 500,000 and 16-gauges having serial numbers starting at 200,000. "The Sportsman" had a three-bird roll-stamping on each side of the receiver. In 1934 DuPont acquired controlling interest of Remington Arms Co., Inc. In 1937, Remington reduced the roll-stamping on "The Sportsman" to one bird on each side and started putting the roll-stamping on Model 11 receivers as well. At the same time, the name "The Sportsman" or "Model 11" began being stamped on the bolt. On Sep. 28, 1937, they stopped the separate serial number sequence in the 2xx,xxx range for the 16-gauge "The Sportsman"; on Aug. 24, 1937, they stopped the separate serial number sequence in the 5xx,xxx range for the 12-gauges and finally on Feb. 14, 1938, they ended the separate serial numbers for the 20-gauge “The Sportsman” at 16,753. From then on the "Model 11" and "The Sportsman" were serial numbered together, continuing the Model 11 sequences. Combined 12-gauge "Model 11" and "The Sportsman" serial numbers reached 499,999 on August 1, 1943. Serial numbers were then jumped to 700,000 and continued.